Conventionally, in a communication system, a communication apparatus performing wireless communication may execute scanning for searching for a connection destination.
However, in executing the scanning, if such a conventional communication apparatus cannot receive a response signal from a scan target, the scan target repeatedly transmits the response signal, thus causing fruitless transmission and reception. In addition, when the communication apparatus performing the scanning cannot receive a response signal from the scan target, the efficiency of the scanning is deteriorated.
Therefore, a feature of the exemplary embodiments provides a communication system, a communication apparatus, a computer-readable storage medium having stored therein a communication program, and a communication method that are capable of suppressing fruitless communication caused when a communication apparatus searches for another communication apparatus, and have increased efficiency of searching.
The exemplary embodiments have the following aspects in order to solve the above problem.
A communication system according to one aspect of the exemplary embodiments includes: a plurality of communication apparatuses, including a search communication apparatus configured to search for another communication apparatus. The search communication apparatus comprises a search request transmission section configured to transmit a search request signal by using a first channel. The search request signal includes information about a second channel different from the first channel.
According to the above aspect, the search request signal includes information about the second channel different from a channel (the first channel) used for transmission of the search request signal. Therefore, by transmitting the search request signal, the information about the second channel is recognized by other apparatuses.
In another aspect, the search communication apparatus may further comprise a use channel determination section configured to select a channel to be used as the second channel from a plurality of predetermined channels in accordance with the ambient communication condition. In this case, the second channel is used for communication other than transmission of the search request signal, and the first channel is one, of the plurality of predetermined channels, that is other than the second channel.
According to the above aspect, the second channel is determined in accordance with the ambient communication condition, instead of being a predetermined channel set in advance. Therefore, the information about a channel (second channel) used by the search communication apparatus for communication other than transmission of the search request signal cannot be recognized by other apparatuses in advance. However, the information about the second channel is recognized by the search communication apparatus transmitting the search request signal.
In another aspect, the search communication apparatus may further comprise a channel switching section configured to switch a channel used for communication. In this case, the channel switching section switches the channel used for communication to the first channel, at the start of a search period in which the search request transmission section can transmit the search request signal, during communication using the second channel, and switches the channel used for communication to the second channel at the end of the search period.
According to the above aspect, during communication using the second channel, the search communication apparatus switches the channel used for communication to the first channel and uses the first channel only during the search period in which the search request signal can be transmitted. Thus, the search communication apparatus can perform communication other than the searching, by using the second channel, during a period other than the search period, in which the search request signal is not transmitted.
In another aspect, the communication system may further include a search subject communication apparatus which is searched for by the search communication apparatus. In this case, the search subject communication apparatus comprises: a search request reception section configured to receive the search request signal; and a search response transmission section configured to transmit, to the search communication apparatus, a search response signal which is a response to the search request signal received by the search request reception section. The search response transmission section transmits the search response signal by using the second channel, based on the information about the second channel included in the search request signal.
According to the above aspect, the search subject communication apparatus transmits the search response signal by using the second channel. Therefore, after the search period has ended, even if the search communication apparatus is performing another communication by using the second channel, the search communication apparatus can receive the search response signal transmitted by the search subject communication apparatus, by using the second channel. That is, even if the search period is short (the period during which the search communication apparatus uses the first channel is short), the search communication apparatus can receive the search response signal by using the second channel, whereby the efficiency of the searching is increased. In addition, since the search subject communication apparatus transmits the search response signal by using the second channel, the search subject communication apparatus can be prevented from continuing to transmit, in vain, a search response signal that the search communication apparatus cannot receive.
In another aspect, the communication system may further include a search subject communication apparatus which is searched for by the search communication apparatus. In this case, the search subject communication apparatus comprises: a search request reception section configured to receive the search request signal; and a search response transmission section configured to transmit, to the search communication apparatus, a search response signal which is a response to the search request signal received by the search request reception section. The search request transmission section transmits information indicating a search period in which the search request signal can be transmitted. The search request reception section receives the information indicating the search period transmitted from the search communication apparatus.
According to the above aspect, the search subject communication apparatus can receive information about the search period, in addition to information about the second channel. Thus, the search subject communication apparatus can recognize the period during which the search communication apparatus uses the first channel. Therefore, the search subject communication apparatus can adjust the period for transmission of the search response signal and/or the channel to be used for the transmission, such that the search response signal can reach (be received by) the search communication apparatus. Thus, the efficiency of the searching by the search communication apparatus is increased, and the search subject communication apparatus can be prevented from continuing to transmit, in vain, a search response signal that the search communication apparatus cannot receive.
In another aspect, based on the information indicating the search period, the search response transmission section may transmit the search response signal by using the first channel, in the search period, and transmit the search response signal by using the second channel, after the search period has elapsed.
According to the above aspect, in the search period, the search subject communication apparatus transmits the search response signal by using the first channel. Therefore, in the search period, the search communication apparatus, which uses the first channel during the search period, can receive the search response signal. In addition, after the search period has elapsed, the search subject communication apparatus transmits the search response signal by using the second channel. Therefore, after the search period has elapsed, the search communication apparatus, which uses the second channel after the search period has elapsed, can receive the search response signal. Thus, the efficiency of the searching by the search communication apparatus is increased, and the search subject communication apparatus can be prevented from continuing to transmit, in vain, a search response signal that the search communication apparatus cannot receive.
In another aspect, based on the information indicating the search period, the search response transmission section may not transmit the search response signal in the search period, and may transmit the search response signal by using the second channel, after the search period has elapsed.
According to the above aspect, in the search period, the search subject communication apparatus does not transmit the search response signal Therefore, the search communication apparatus does not need to wait for the search response signal in the search period. Therefore, the search period can be finished in a short period. After the search period has ended, the search subject communication apparatus transmits the search response signal by using the second channel Thus, it is ensured that the search response signal reaches (is received by) the search communication apparatus in the period during which the search communication apparatus uses the second channel. Thus, the efficiency of the searching by the search communication apparatus is increased, and the search subject communication apparatus can be prevented from continuing to transmit, in vain, a search response signal that the search communication apparatus cannot receive.
In another aspect, the information indicating the search period may be included in the search request signal, and may be transmitted by the search request transmission section.
According to the above aspect, by receiving the search request signal, the search subject communication apparatus can recognize the search period (that is, the period during which the search communication apparatus uses the first channel).
In another aspect, the search request transmission section may transmit a search end notification signal as the information indicating the search period, at the end of the search period.
According to the above aspect, the search subject communication apparatus can recognize, as the search period (that is, the period during which the search communication apparatus uses the first channel), the period from when the search request signal has been received to when the search end notification signal is received.
In the above, the exemplary embodiments are described using a communication system as an example. However, the exemplary embodiments may be applied to a communication apparatus, a computer-readable storage medium having stored therein a communication program, or a communication method.
According to the exemplary embodiments, it is possible to provide a communication system and the like that are capable of suppressing fruitless communication caused when a communication apparatus searches for another communication apparatus, and have increased efficiency of searching.
These and other objects, features, aspects and advantages of the exemplary embodiments will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.